Typewriting machine



May 23, 1944. w. HELMOND 2,349,723

TYPEWRITING MACHINE Filed May 12, 1941 BY &

' ATTORNEY Patented May 23, 1944 UNITE s'rA'rEs PATENT OFFICE milm Application 12, 1.41, Serial No. 392,997 This invention relates tovcase-shift mecha-G 197-") flciaims.

nisms for typewriting machines, and more par ticuiarly to stops for arresting the shiftable'member of such mechanisms in either position.

One of the objects of the invention is to provide an improved case-shift stop organization effective to limit the extent of movement of the caseshifting member with quietness and dependable accuracy.

Another object is to provide a case-shift stop mechanism in which a sound-deadening stop'element is arranged to engage angppofite stop over a broad contact area and with a self-seating action so as to arrest the case-shift element without inducing practically any sound.

Another object is to provide a case-shift stop mechanism having a one-piece vibration-absorbing or impact-dampening element arranged to coact with confronting counterstops to quietly arrest the shiftable element at either case position.

A further object is to provide an improveddouble stop element for case-shift mechanisms, presenting a substantially solid, block-like body adapted for economic fabrication from a suitable sound-dampening material such as rubber or the like.

In the drawing:

Figure 1 is a fragmentary elevational view taken on a plane transverse of the typewriter, illustrating one embodiment which the invention may assume in practice,

Figure 2 is a side elevational view taken on'a plane indicated at line 2--2 of Figure 1 showing the case-shift element in normal upper-case position, and

Figure 3 is a fragmentary side elevation of the stop organization with the case-shift member in lower-case position.

Referring to the drawing, a segment frame I carries a type-bar segment i for pivotal support of a series of type bars I having upperand lower-case type thereon adapted to strike a platen I when the frame 5 is shifted to either case position. The segment frame 5 is mounted for caseshift movement on the main frame of the machine, of which one side member II is shown, by roller-bearing units ii at each side of its upper region. At its lower part the segment frame 5 is mounted by arms l2 of a rockable shaft It pivoted on the mainframe by trunnions M. the rock shaft acting as an equalizer to assure parallel movement of the t frame. In quiescent position, the

type bars I lie against a type-bar rest I! which 5 mately'parallel with the corresponding counteris supported on the segment frame 6 for movement therewith. Case-shift movement of the segment frame may be effected by the usual keyoperable shift lever, not shown, which may be operatively connected to the segment frame I by a link It. A spring ll', held at one end to the segment frame and anchored on the main frame, yieldably holds the segment frame, and therefore the type-bar basket, in normal upper-case position.

A stud 20 carried on the segment frame I, and projecting laterally therefrom, provides a pivotal attachment to the frame 6 for thearms l2 of the rock shaft and extends beyond said arms to provide a headed bearing 2| on which a stop block 22 is rotatably carried. A collar portion 22 of the stud abuts arm i2 and, in conjunction with the head of bearing 2|, retains the block 22 in its lateral position on the bearing. The stop block 22 is preferably of solid rectangularform having upper and lower stop faces and a bore therethrough parallel to the stop faces, in which bore the bearing 2i is joumaled. The material of which the block 22 is formed is preferably elastic and relatively soft, having soundor vibrationdampening characteristics. A block of semi-soft rubber or like material has been found to be most suitable in that such material may yield slightly under impact but will immediately resume its normal size and shape and maintain same after numerous blows. At each limit of case-shift movement of the segment frame 5, the stop block 22 engages oppositely arranged confronting abutments or counterstops 24, each adjustably carried on the side member I. of the main frame. This side member has a cut-out 25 from which two laterally-projecting lugs 26 are extruded,each of these lugs being threaded to receive the screw shank of the corresponding counterstop 24. The head of each counterstock is relatively large to aiford a broad face for engagement by the corresponding face of the block 22. The counterstop head is knurled on its periphery for convenience in screwing same to the desired position of adjustment, in which position it is secured by a lock nut 21. The adjusted position of each counterstop determines the registry of the upperand lower-case type with the printing line on the platen I, in the usual manner.

It is desirable to have the block 22 snugly fitted onthebearing 2i soastobe relativelyfreeto turn and yet maintain substantially its normal position, that is; with its stop faces approxof the segment frame and would thus throw out the registry of the upperor lower-case type with the printing line on the platen.

It may be noted that, in the kind of shift mounting of the segment frame of which the illustrated embodiment is typical, the lower portion of the shift frame moves through an, arc

generated by the swinging of the rock shaft arms H, which may cause the segment frame to assume a slightly different angle in either the upperor lower-case positions. When moving from one case position, the stop block 22 is aligned with the counterstop 24 with which it has been engaged and, as it approaches the opposite counterstop, the block is brought into alignment therewith by the rotation of same on its bearing 2|. Also, as the block 22 leaves the engaged counterstop, there may be a tendency of the block face to adhere slightly to the counterstop until it actually leaves same, this adherence causing the block 22 to be displaced slightly from its aligned position. This momentary disaligmnent of the block with the counterstops, whether caused by the angular displacement of the segment frame or by the slight adhesion of the block to the counterstop, is advantageous in quietly arresting the shift frame by avoiding a slapping of the block against the counter'stop face, at the same time assuring accurat arrest by aligning itself quickly with the engaged counterstop.

While the rotative displacement of the block 22 is advantageous in eliminating a noisy arrest, the use of a solid, massive body of vibration-absorbing material for the block, in itself, renders the case shift stopping practically noiseless. The block 22 presents a stop element that may be produced very economically, and is adapted for fastening by simple means, in position in the 3 case-shift mechanism.

In the physical embodiment of the invention illustrated by way of example, the improved stop organization is shown in a typewriter of the segment-shift or basket-shift type wherein the shiftable member is usually the type-bar segment frame. It will be understood, however, that the invention may be embodied in typewriters of other kinds such as platen-shift machines,- for limiting case-shift movement of the platen-supporting member.

What is claimed is:

1. Ina typewriter case-shift mechanism having two members relatively movable in case shifting, means for quietly and accurately limiting the relative movement, comprising a part on each of said members, each part presenting a relatively broad, flat, impact-receiving face, at least one of said parts being mounted for rocking movement bodily about an axis intermediate the border of itsface,toallowthefacesofsaidpartstoalign with each other upon contact.

2. In a typewriter case-shift mechanism having two members relatively movable in case shifting, means for quietly and accurately limiting tin relative movement, comprising a part on each of said members, each part presenting a relatively broad, flat impact-receiving face, one of said parts being mounted for pivotal movement bodily about an axis disposed intermediate the lateral limits of its face and transverse to the direction of relative movement, to allow the faces of said partsto align with each other upon impact.

3. In a case-shift mechanism for a typewriter having two members relatively, movable in case shifting, means to limit the case-shift movement,

comprising, abutments on one of said members.'

and a block of impact-dampening material pivotally mounted on the other of said members and having broad areas engageable with said abutments.

4. In a case-shift mechanism-for a typewriter having two members relatively movable in case shifting, means to limitthe case-shift movement, comprising, abutments on one of said memb'ers, and a rectangular block of vibrationabsorbing material engageable with said abutments and pivotally mounted on the other of said members on an axis substantially at right angles to the direction of case-shift movement.

5. In a case-shift mechanism for a typewriter having two members relatively movable in case shifting, means to limit the case-shift movement, comprising, abutments on one of said members, a stud on the other of said members projecting therefrom substantially at right angles to the direction of case-shift movement, and a substantially solid block of rubber or the like presenting opposite faces engageable with said abutments and having a bore between said faces bearing on said stud.

6. As anew article of manufacture, a stop element for use in a case-shift mechanism for typewriters, to quietly and accurately arrest caseshift movement, said element comprising a generally rectangular block of rubber or the like presenting oppositely facing substantially flat stop faces parallel with each other and having a bore intermediate said faces for pivotally mounting said block.

WILLIAM F. HELMOND. 

